JP2007098532A - Hand tool and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a hand tool for easily imparting desired hardness to only an action part of a chisel or hammer, etc., in the hand tool requiring the prescribed hardness. <P>SOLUTION: This hand tool performs prescribed processing treatment by applying striking force by the action part (a blade part 2) at a distal end to a processed object. In the manufacturing method, welded metal 2a by a welding member is built up at the distal end part cut and removed in advance by using the welding member provided with the desired hardness, and the action part is formed by subsequently performing grinding treatment into a prescribed shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hand-held tool used for cutting or cutting a stone material such as a cut hammer or chisel, a brick or a block, or a hand-held tool such as a hammer for applying a predetermined hit to an object.

  A hand-held tool such as a cut hammer or chisel requires a predetermined hardness at a predetermined cutting edge portion. However, when special processing is applied only to the tip, the tool main body (described in Patent Document 1 is described). In general, a tool having such a handle portion is manufactured by forming all of the purpose (except for the handle portion) from an appropriate material and performing a predetermined heat treatment.

  In particular, as a means for forming the tip portion of a material different from that of the main body, Patent Document 2 (Japanese Patent Laid-Open No. 11-11241) embeds a cemented carbide fracture portion (for window glass crushing) at the tip of the stainless steel main body. An instrument is disclosed.

  In addition, as a special manufacturing means other than a hand-held tool, Patent Document 3 (Japanese Patent Laid-Open No. 5-77172) discloses that a tapered end portion of a bit having a cutting edge portion formed at a tip portion thereof is fitted by a tapered fitting. There is disclosed a splinter in which the attached intermediate holder and the chisel body are connected by a partial fit between the fit part of the chief holder and the fit hole of the chisel body.

  In Patent Document 4 (Japanese Patent Laid-Open No. 11-245222), the working area (tip blade part), the shaft area, and the insertion area (machine body mounting part) are made of different materials as means for forming them. It is disclosed that the respective regions are joined by friction welding, or induction quenching conditions are changed (change in quenching feed rate in an induction heating furnace, etc.).

Design Registration No. 1011978. JP-A-11-11241. Japanese Patent Laid-Open No. 5-77172. JP-A-11-245222.

  When trying to make the working portion of the tip have a desired hardness, it is necessary to perform a predetermined heat treatment of the entire main body, and the unnecessary portion (shaft region) is also heat-treated, which increases waste. In particular, if the overall hardness is increased, when used as a hand-held tool, the tool holding hand will be subjected to a strong impact when hitting the main body, and increasing the hardness will increase the manufacturing cost due to the heat treatment cost. End up.

  Further, as described in Patent Documents 2 and 3, when only the action portion at the tip is formed of a separate member (for example, a carbide tip), the member is formed as a fitting structure or a welding structure by welding. However, in the case of a hand-held tool, since the relevant part is a fine part, it is complicated to produce an accurate fitting structure, and accurate positioning is also required for welding, which is also complicated to produce. is there. In addition, unless the connection part (fitting part or welding part) is formed firmly, the tip member will be peeled off during use, resulting in high manufacturing costs.

  Also, brazing means to the main body of another member (hard member) is known as a general means. However, in a tool that receives an impact, the brazed portion is immediately separated, and there is a problem in durability of the tool. is there.

  Therefore, the present invention proposes a tool manufacturing method that can increase the hardness of the working part such as the blade part at a low cost by a completely different means.

  A hand-held tool and a manufacturing method thereof according to the present invention use a welding member having a desired hardness in a hand-held tool that performs a predetermined processing process by applying a striking force by a working portion at a tip to a workpiece. In this case, a weld metal by a welding member is placed on the tip portion cut in advance, and then a predetermined shape is subjected to a grinding process to form an action portion.

  Therefore, without subjecting the main body to special heat treatment or processing (processing such as forming a fitting structure, but preparation for welding is necessary), and without welding another member such as a carbide tip, Since the weld metal itself constitutes the action part, the action part can be produced to a desired hardness by selecting the weld metal.

  Since the present invention adopts the above-described configuration, it is possible to easily obtain a tool having an action portion having a desired hardness without subjecting the tool body to heat treatment or special processing. Even if there is a slight change in the shape of the action portion, it can be flexibly accommodated.

  Next, an example in which the embodiment of the present invention is applied to a chisel will be described. As is well known, the chisel is provided with a cutting blade (operating portion) 2 at the tip of the rod-shaped main body 1, and the rod-shaped main body 1 is formed of an appropriate tool steel as in the prior art. The part 2 is formed in a cut-out state (FIG. 2A).

  Next, the welding member is melted at the formation portion of the blade portion 2 and the weld metal 2a is placed in an appropriate shape (FIG. 2B). As a welding member, for example, a flux-cored wire (MT-700: the components of the deposited metal are as shown in the table of FIG. 3) for carbon dioxide arc welding having a Vickers hardness of about 700, which is used for welding of excavating equipment, is used. Overlay welding is performed by a gas welding machine. After the build-up welding is finished, a predetermined post-heat treatment is performed and the steel is gradually cooled.

  After the slow cooling, the arrangement portion 2a is subjected to predetermined grinding and polishing to form a predetermined shape (the shape of the blade portion 2).

  The result of measuring each hardness of the chisel produced according to the above technique (product of the present invention), a commercially available highly heat-treated product, each tip of a general chisel, the base of the blade, and the main body. As shown in FIG.

  Therefore, the product according to the present invention has a hardness higher than that required by the blade portion (action portion) 2, and the main body 1 has flexibility without being increased in hardness due to useless heat treatment. This reduces the impact on the hand during hand-held work.

  Moreover, since the blade portion (action portion) 2 is formed by welding, it has superior impact resistance compared to brazing, and the blade portion does not separate.

  The present invention is not limited to the above-mentioned chisel, but can be applied to all hand-held tools that require a desired hardness only at a predetermined location.

It is explanatory drawing of the chisel of embodiment of this invention, (a) is a front view (b) is a top view. In the explanatory view of the manufacturing process, (a) shows the state before (b) after the placement and (c) after the grinding. Table showing the components of the welded parts Hardness comparison table of the product of the present invention and commercial products.

Explanation of symbols

1 Body 2 Blade (action part)
2a Weld metal (filled)

Claims (5)

  In a hand-held tool that performs a predetermined processing process by applying a striking force by a working part at the tip to a workpiece, a welding member having a desired hardness is used, and welding is performed on the tip portion that has been excised in advance. A method for manufacturing a hand-held tool, wherein a working part is formed by placing a metal and then grinding a predetermined shape.   The method for manufacturing a hand-held tool according to claim 1, wherein the action part is a cutting blade part.   The method for manufacturing a hand-held tool according to claim 2, wherein a flux-cored wire for carbon dioxide arc welding, which has a Vickers hardness of about 700, is used as the weld metal.   In a hand-held tool that performs a predetermined processing process by applying a striking force by an action part at the tip to a workpiece, the action part of the main body is provided with a welding metal having a desired hardness, and then a predetermined value. A hand-held tool characterized by being formed by grinding a shape.   The hand-held tool according to claim 4, wherein the action part is a cutting blade part.

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